The present invention relates, in general, to electronics, and more particularly, to methods of forming semiconductor devices and structure.
In the past, the semiconductor industry utilized various methods and structures to build boost mode driving circuits for light emitting diodes (LEDs). The boost mode driving circuit was used to regulate the current through the LED in order to control the light intensity of the LED. For some applications, the boost mode driving circuit had a control pin that was pulsed in order to control the current, thus, the light intensity of the LED. During the operation, there were current spikes or inrush current. In some cases, the in-rush current disturbed the control circuit operation and reduced the accuracy of the current control. The in-rush current increased the power dissipation of the system and could also cause undesirable electromagnetic radiation (EMI).
Accordingly, it is desirable to have an LED controller that minimizes inrush current, that minimizes EMI, and that more accurately controls the current through the LED.
For simplicity and clarity of the illustration, elements in the figures are not necessarily to scale, and the same reference numbers in different figures denote the same elements. Additionally, descriptions and details of well-known steps and elements are omitted for simplicity of the description. As used herein current carrying electrode means an element of a device that carries current through the device such as a source or a drain of an MOS transistor or an emitter or a collector of a bipolar transistor or a cathode or anode of a diode, and a control electrode means an element of the device that controls current through the device such as a gate of an MOS transistor or a base of a bipolar transistor. Although the devices are explained herein as certain N-channel or P-Channel devices, a person of ordinary skill in the art will appreciate that complementary devices are also possible in accordance with the present invention. It will be appreciated by those skilled in the art that the words during, while, and when as used herein are not exact terms that mean an action takes place instantly upon an initiating action but that there may be some small but reasonable delay, such as a propagation delay, between the reaction that is initiated by the initial action.